VC ATL, ATL And VB Callback

Johan Eriksso
#1 / 9

ATL And VB Callback

I want to have a Service (VC++) which has a method (Connect) that receives a
backpointer to the caller. The problem is that the caller is a VB component
who passes an interface through which the VC++ program may execute any
callbacks. i.e. VC++ receives a reference to a VB object..... Does
anyone know if this is even remotely possible ?

/Johan Eriksson

Fri, 19 Dec 2003 04:14:50 GMT

amit de
#2 / 9

ATL And VB Callback

Hi,
this is possible. pl. check my article on idevresource.com(esp. the vbtimer
sample). you might find it illuminating. :-)

amit.

Quote:

> I want to have a Service (VC++) which has a method (Connect) that receives a
> backpointer to the caller. The problem is that the caller is a VB component
> who passes an interface through which the VC++ program may execute any
> callbacks. i.e. VC++ receives a reference to a VB object..... Does
> anyone know if this is even remotely possible ?

> /Johan Eriksson

Fri, 19 Dec 2003 07:54:56 GMT

AQua
#3 / 9

ATL And VB Callback

hi,amit:
I search the www.idevresource.com,
and can not find your article.
Please tell me how to find your article?
thanks!
Aquan
2001/07/02

Fri, 19 Dec 2003 10:02:22 GMT

amit de
#4 / 9

ATL And VB Callback

Hi,
at www.idevresource.com , try the COM section, it must be there. else
you can also try www.codeproject.com under the ATL section (probably).
In the VB/VC eventing article there a VBTimer sample that might help U.
amit.

Quote:

> hi,amit:
> I search the www.idevresource.com,
> and can not find your article.
> Please tell me how to find your article?
> thanks!
> Aquan
> 2001/07/02

Sat, 20 Dec 2003 11:48:48 GMT

Mr07
#5 / 9

ATL And VB Callback

Absolutely. Unless you are talking about asynchronous calls you can just
call back on that interface w/o any attention to the fact that it is coming
from VB coclass (coclass is a coclass after all in whatever language you
manage to write it) :-)

--
Sanin Saracevic, MCP
Lead Software Architect
Interland, Inc.

Quote:

> I want to have a Service (VC++) which has a method (Connect) that receives
a
> backpointer to the caller. The problem is that the caller is a VB
component
> who passes an interface through which the VC++ program may execute any
> callbacks. i.e. VC++ receives a reference to a VB object..... Does
> anyone know if this is even remotely possible ?

> /Johan Eriksson

Sat, 20 Dec 2003 13:56:10 GMT

AQua
#6 / 9

ATL And VB Callback

I find it at http://www.codeproject.com/
Thank U :)

Quote:

> Hi,
> at www.idevresource.com , try the COM section, it must be there. else
> you can also try www.codeproject.com under the ATL section (probably).
> In the VB/VC eventing article there a VBTimer sample that might help U.
> amit.

> > hi,amit:
> > I search the www.idevresource.com,
> > and can not find your article.
> > Please tell me how to find your article?
> > thanks!
> > Aquan
> > 2001/07/02

Sat, 20 Dec 2003 14:30:31 GMT

Johan Eriksso
#7 / 9

ATL And VB Callback

Thanks Amit ! Finally found the article (Ive read a few other from you,
all very informative). Ill try this stuff
as soon as I get a chance, glanced through the article though and liked what
I saw ! Great stuff !

Do you see any problems regarding several Events in the VB Component ?

Thanks again

/Johan Eriksson

Quote:

> Hi,
> this is possible. pl. check my article on idevresource.com(esp. the
vbtimer
> sample). you might find it illuminating. :-)

> amit.

> > I want to have a Service (VC++) which has a method (Connect) that
receives a
> > backpointer to the caller. The problem is that the caller is a VB
component
> > who passes an interface through which the VC++ program may execute any
> > callbacks. i.e. VC++ receives a reference to a VB object..... Does
> > anyone know if this is even remotely possible ?

> > /Johan Eriksson

Mon, 22 Dec 2003 04:07:20 GMT

Johan Eriksso
#8 / 9

ATL And VB Callback

Hmmm.... unfortunately it must be asynchronous....
And to add some extra spice there are 4 different methods in the VC
Component
through which the VB Component may communicate AND 4 corresponding methods
in the VB Component that VC uses to fire the callbacks...

Thanks anyway

/Johan Eriksson

Quote:

> Absolutely. Unless you are talking about asynchronous calls you can just
> call back on that interface w/o any attention to the fact that it is
coming
> from VB coclass (coclass is a coclass after all in whatever language you
> manage to write it) :-)

> --
> Sanin Saracevic, MCP
> Lead Software Architect
> Interland, Inc.

> > I want to have a Service (VC++) which has a method (Connect) that
receives
> a
> > backpointer to the caller. The problem is that the caller is a VB
> component
> > who passes an interface through which the VC++ program may execute any
> > callbacks. i.e. VC++ receives a reference to a VB object..... Does
> > anyone know if this is even remotely possible ?

> > /Johan Eriksson

Mon, 22 Dec 2003 05:38:03 GMT

Mr07
#9 / 9

ATL And VB Callback

Still does not sound like a show stopper. You will definitely experience low
performance since VB coclasses are single threaded, so if you call back from
two different threads within your C++ component calls will be serialized by
COM message dispatcher.

--
Sanin Saracevic, MCP
Lead Software Architect
Interland, Inc.

Quote:

> Hmmm.... unfortunately it must be asynchronous....
> And to add some extra spice there are 4 different methods in the VC
> Component
> through which the VB Component may communicate AND 4 corresponding methods
> in the VB Component that VC uses to fire the callbacks...

> Thanks anyway

> /Johan Eriksson

> > Absolutely. Unless you are talking about asynchronous calls you can just
> > call back on that interface w/o any attention to the fact that it is
> coming
> > from VB coclass (coclass is a coclass after all in whatever language you
> > manage to write it) :-)

> > --
> > Sanin Saracevic, MCP
> > Lead Software Architect
> > Interland, Inc.

> > > I want to have a Service (VC++) which has a method (Connect) that
> receives
> > a
> > > backpointer to the caller. The problem is that the caller is a VB
> > component
> > > who passes an interface through which the VC++ program may execute any
> > > callbacks. i.e. VC++ receives a reference to a VB object..... Does
> > > anyone know if this is even remotely possible ?

> > > /Johan Eriksson

Tue, 23 Dec 2003 22:54:23 GMT